CN212303125U - Easily-bent flexible transmission line - Google Patents

Abstract

The application provides an easily-bent flexible transmission line which comprises a metal ground, a signal layer and a dielectric layer. The transmission line is composed of a plurality of metal grounds, a dielectric layer and a signal layer, wherein the plurality of metal grounds form a multi-layer structure of the transmission line, the dielectric layer is filled between the plurality of metal grounds, and the signal layer is embedded in the dielectric layer. And the top layer metal ground positioned on the top surface of the medium layer and the bottom layer metal ground positioned on the bottom surface of the medium layer are provided with buffer holes in the bending area. The transmission line that this application provided windows in the region of buckling and subtracts the copper design, can make soft transmission line can accomplish required processing of buckling under the prerequisite of guaranteeing soft transmission line radio frequency performance to it can also alleviate the technology degree of difficulty to subtract copper in the region of buckling. The problem of traditional soft transmission line resilience force and the degree of difficulty of bending are big, be not convenient for bend is solved.

Description

Easily-bent flexible transmission line

The present application claims priority from the chinese patent application entitled "an easily bendable flexible transmission line" filed by the chinese patent office on 19/5/2020, application number 202010422842.1, the entire contents of which are incorporated herein by reference.

Technical Field

The application relates to the technical field of signal transmission, in particular to an easily-bent flexible transmission line.

Background

A transmission line is a communication element for transmitting signals. With the rapid development of communication technology, the signal transmission performance requirements for communication devices are becoming higher and higher. In view of the transmission characteristics of large capacity, high frequency and high speed signals in 5G communication, the transmission efficiency of internal signals of the terminal equipment and the utilization rate of internal space are particularly important. In order to realize signal transmission, the terminal equipment can use a circular coaxial line to complete signal transmission. However, under the conditions of various terminal functions, complex equipment modules and a large increase in the number of antennas, the number of signal transmission lines required by the terminal is also increasing. Therefore, it is difficult for the conventional circular coaxial transmission line to satisfy signal transmission requirements.

In order to adapt to the signal transmission efficiency and improve the space utilization rate of the terminal equipment, a flexible transmission line can be adopted to replace a circular coaxial transmission line. A typical flexible transmission line usually uses a flexible material to wrap a transmission copper layer so as to be able to bend. The adopted soft materials are LCP, modified PI, fluorine-containing PTFE and the like, and the integration and the flexibility of the soft transmission line are utilized to adapt to the overall size of the terminal equipment and the space layout requirement inside the terminal equipment.

At the bending position of the flexible transmission line, the flexible transmission line can be bent at a certain angle, so that the transmission line is conformal with the internal space. However, the flexible transmission line has three or more copper layers inside, so that the flexible transmission line has high hardness during bending, and is easy to bend to a predetermined angle or break. And along with the number of piles of the copper layer in soft transmission line is more and whole thickness is thicker, its resilience force and the degree of difficulty of bending are bigger for when installing soft transmission line in terminal equipment, very easily because soft transmission line hardness is great or resilience force is great, it is not hard up or even drops in the inside of terminal, thereby influence the transmission performance of soft transmission line and the function of whole equipment.

SUMMERY OF THE UTILITY MODEL

The application provides a soft transmission line easily bends to it is big with the degree of difficulty of bending to solve the soft transmission line resilience force of tradition, the problem of bending not convenient for.

The application provides an easily-bent flexible transmission line, which comprises a metal ground, a signal layer and a dielectric layer; the dielectric layer is filled between the multiple layers of metal grounds, and the signal layer is embedded in the dielectric layer;

the multilayer metal ground comprises: the top layer metal ground is positioned on the top surface of the dielectric layer, and the bottom layer metal ground is positioned on the bottom surface of the dielectric layer; and buffer holes are formed in the bending areas of the top metal ground and the bottom metal ground so as to improve the bending performance of the flexible transmission line.

Optionally, the flexible transmission line further includes a metal post; the metal column penetrates through the multiple layers of metal grounds to connect the top layer metal ground and the bottom layer metal ground to isolate the signal layers.

Optionally, the signal layer includes a signal line; the metal posts are arranged on two sides of the signal line to improve the isolation of the signal line.

Optionally, the signal layer further includes a power line and a control line; the power line and the control line are embedded into the dielectric layer; the power line and the control line are respectively arranged on two sides of the signal line so as to isolate the signal line, the power line and the control line through the metal column.

Optionally, the buffer hole is disposed in an orthographic projection area of the power line and the control line to the top metal ground and the bottom metal ground.

Optionally, the buffer holes are a plurality of hole structures uniformly arranged in the bending region.

Optionally, the buffer hole is a hollow structure arranged in the bending area.

Optionally, the dielectric substrate of the dielectric layer is LCP, MPI, or PTFE.

Optionally, the flexible transmission line further includes a connector; the connectors are arranged at two ends of the flexible transmission line; the connector is connected with the signal layer to transmit signals.

According to the above technical scheme, the application provides an easily bendable flexible transmission line, which includes a metal ground, a signal layer and a dielectric layer. The transmission line is composed of a plurality of metal grounds, a dielectric layer and a signal layer, wherein the plurality of metal grounds form a multi-layer structure of the transmission line, the dielectric layer is filled between the plurality of metal grounds, and the signal layer is embedded in the dielectric layer. And the top layer metal ground positioned on the top surface of the medium layer and the bottom layer metal ground positioned on the bottom surface of the medium layer are provided with buffer holes in the bending area. The transmission line that this application provided windows in the region of buckling and subtracts the copper design, can make soft transmission line can accomplish required processing of buckling under the prerequisite of guaranteeing soft transmission line radio frequency performance to it can also alleviate the technology degree of difficulty to subtract copper in the region of buckling. The problem of traditional soft transmission line resilience force and the degree of difficulty of bending are big, be not convenient for bend is solved.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an easy-bending flexible transmission line according to the present application;

FIG. 2 is a schematic cross-sectional view of a flexible transmission line according to the present application;

FIG. 3 is a schematic diagram of an internal trace structure of a signal layer according to the present application;

fig. 4 is a schematic structural view of a bending region of the present application.

Detailed Description

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following examples do not represent all embodiments consistent with the present application. But merely as exemplifications of systems and methods consistent with certain aspects of the application, as recited in the claims.

In the technical scheme provided by the application, the transmission line can be applied to signal transmission designs of various electronic communication devices, such as mobile phones, tablet computers, notebook computers and the like. The transmission line can have different data transmission functions according to the arrangement mode and the connection relation of the devices in the terminal equipment. In addition, when the internal device layout of the terminal device is provided, it is necessary to bend the terminal device in a partial region so as to adapt to the shape of another component. For example, when the height difference of the components connected to both ends of the transmission line is different, it is necessary to provide a plurality of bending regions on the transmission line depending on the shape of the housing of the terminal device. In the bending region, the transmission line as a whole needs to be bent.

Fig. 1 is a schematic structural diagram of an easily bendable flexible transmission line according to the present application; fig. 2 is a schematic cross-sectional structure diagram of the flexible transmission line of the present application. As shown in fig. 1 and fig. 2, the present application provides an easy-to-bend flexible transmission line, which includes a metal ground 1, a signal layer 2, and a dielectric layer 3. The metal ground 1, the signal layer 2 and the dielectric layer 3 form a transmission line with a multilayer structure. The dielectric layer 3 is filled in a space area among the plurality of layers of metal grounds 1, and the signal layer 2 is embedded into the dielectric layer 3, so that the metal grounds 1 can protect and shield the signal layer 2 and the dielectric layer 3, and signal transmission is completed.

In practical applications, the transmission line includes at least two layers of metal lands 1, as shown in fig. 2, the multiple layers of metal lands 1 include: a top layer metal ground 11 on the top surface of the dielectric layer 3 and a bottom layer metal ground 12 on the bottom surface of the dielectric layer 3. Besides the function as a reference ground, the top layer metal ground 11 and the bottom layer metal ground 12 can also play a role in shielding interference, and can play a role in helping when performing electromagnetic compatibility processing on the inside of the terminal equipment.

It should be noted that the top layer and the bottom layer are merely used for orientation differentiation for convenience of description, and do not limit the installation position and the application posture of the overall transmission line. Only one layer of metal ground 1, which is located at the topmost part of the dielectric layer 3, is referred to as top layer metal ground 11 in this application; the metal ground 1 located at the bottommost portion of the dielectric layer 3 is referred to as a bottom metal ground 12. In practical application, the number of layers of the metal ground 1 is not limited, and the metal ground can be designed according to practical requirements. For example, a metal ground 1 may be added to the dielectric layer 3 according to the actual signal transmission requirement, so as to provide an additional reference ground. The number of layers of the metal ground 1 or the thickness of the metal ground 1 can be increased in order to increase the overall strength of the transmission line and to better protect the wires such as the internal signal line.

In order to adapt to the bending structure, the top metal ground 11 and the bottom metal ground 12 are provided with buffer holes 4 in the bending area, so as to improve the bending performance of the flexible transmission line. In this application, buffer hole 4 is for evenly setting up a plurality of trompil structures in the region of bending, perhaps, buffer hole 4 is for setting up hollow out construction in the region of bending.

In practical application, the metal ground 1, the signal layer 2 and the dielectric layer 3 need to be bent in the bending region. Therefore, small holes can be formed in the top layer metal land 11 and the bottom layer metal land 12, the size and the shape of the holes are not limited, the holes can be independent holes, and copper can be removed in a whole piece; the shape of the aperture may be circular, square, rectangular and any other shape. If the signal layer 2 has enough space, the metal ground 1 on the signal layer 2 can be hollowed out to remove copper, so that the bending performance of the flexible transmission line in the bending area is further improved.

Therefore, compared with the traditional method in which the trace of the bending area is changed from the strip line to the microstrip line for layer reduction, the method not only can well improve the bending performance of the product and enable the structure of the product to tend to be stable, but also can overcome the impedance sudden change of the flexible transmission line caused when the strip line is converted into the microstrip line in the bending area in the traditional method, and improve the radio frequency performance of the transmission line.

Moreover, the design of windowing and copper reduction in the bending area can ensure that the flexible transmission line can complete the required bending treatment on the premise of ensuring the radio frequency performance of the flexible transmission line. Through set up the buffer hole in the regional of bending of top layer metal place 11 and bottom layer metal place 12, can improve the yielding degree of transmission line in the regional of bending to when needs are bent, can accomplish smoothly and bend, improve the bending performance. Wherein. The bending performance is a comprehensive evaluation index of the flexible transmission line, and comprises the aspects of easiness in bending, deformation degree after bending, influence on signal transmission quality after bending and the like.

Meanwhile, compared with a transmission line obtained by a conventional layer reduction design mode, the flexible transmission line provided by the application only needs to be subjected to copper reduction treatment such as punching, hollowing and the like in bending areas of the top layer metal ground 11 and the bottom layer metal ground 12, a complex pressing process is not needed, and the process difficulty is reduced.

In some embodiments of the present application, the flexible transmission line further includes a metal pillar 5; the metal pillar 5 penetrates through the multiple layers of metal grounds 1 to connect the top layer metal ground 11 and the bottom layer metal ground 12, and isolates the signal layer 2. The metal posts 5 may be formed by stacking the metal ground 1, the signal layer 2, and the dielectric layer 3 layer by layer, and then punching holes in a direction perpendicular to the layers, and then inserting the metal posts 5 into the punched holes, so as to connect the top metal ground 11 and the bottom metal ground 12. In addition, since the top layer metal ground 11 and the bottom layer metal ground 12 are both grounded and subjected to 0-bit processing, such as grounding, as a reference ground, the metal pillar 5 has the characteristic of being referenced to the ground by 0 potential, thereby isolating the signal layer 2 and improving the signal transmission performance of the signal layer 2.

Further, the signal layer 2 includes a signal line 21. In practical applications, the transmission line has a plurality of rows of traces, wherein different traces are used for transmitting different data signals. And the signal line 21 may be any one or more rows of the plurality of rows of traces, i.e. the traces for transmitting signals in the transmission line. In order to isolate the signal line 21, the metal posts 5 are disposed on both sides of the signal line 21 to improve isolation of the signal line.

In order to facilitate the arrangement of the metal posts 5, in practical applications, the signal line 21 may be disposed at a middle position of the entire signal layer 2, the signal line 21 extends along the overall extension direction of the transmission line, and the metal posts 5 may be disposed in pairs at two sides of the signal line. Accordingly, in order to obtain a better signal line shielding effect, a plurality of pairs of metal posts 5 may be uniformly arranged along the overall extension direction of the transmission line. For example, as shown in fig. 2, the metal posts 5 are respectively located at two sides of the rf signal line 21 and penetrate through the three-layer structure of the top layer metal ground 11, the signal layer 2 and the bottom layer metal ground 12, so that the rf signal line 21 has better isolation, and the signal is prevented from being affected by interference of external electromagnetic waves or other factors during transmission in the signal line 21.

Further, the signal layer 2 further includes a power supply line 22 and a control line 23. In practical applications, the power line 22 may be used to supply power to devices connected to either end of the transmission line, such as a feed circuit connected to an antenna; control lines 23 may be used to pass control signals to drive devices connected on either end. The signal line 21, the power line 22 and the control line 23 may be arranged at the same level, i.e. all arranged at an intermediate level of the transmission line, and correspondingly, the power line 22 and the control line 23 are also embedded in the dielectric layer 3.

In order to fully utilize the whole space of the transmission line and have better signal isolation performance, the power line 22 and the control line 23 are respectively arranged at two sides of the signal line 21 so as to isolate the signal line 21, the power line 22 and the control line 23 through metal columns. For example, as shown in fig. 2 and 3, the signal line 21 is disposed at a central position of the transmission line signal layer 2, and the power supply line 22 is disposed in a side region of the signal line 21 (right side region in fig. 2); the control line 23 is provided in the other side region (left side region in fig. 2) of the signal line 21. Wherein, the power line 22 and the control line 23 can be provided with a plurality of wires according to the functional requirements of the actual connecting component. For example, 3 signal lines 21 may be disposed in the left area of fig. 2, and 1 power line 22 may be disposed in the right area, in practical applications, power is supplied to one end device through the power line 22, and different control signals are transmitted through the plurality of signal lines 21, so as to ensure the normal operating state of the connected device.

In the bending region, the metal ground 1, the internal wiring and the dielectric substrate are required to be bent, wherein the electric signals transmitted in the signal line 21 are easily affected by the bending structure during bending; the electrical signals transmitted in the power line 22 and the control line 23 are generally less affected by the bending structure, so that the transmission quality of the electrical signals in the signal line 21 is ensured. Specifically, the signal line 21 needs to maintain the isolation effect of the top layer metal ground 11 and the bottom layer metal ground 12 in the bending region, and in order to obtain better bending performance, holes need to be formed in the top layer metal ground 11 and the bottom layer metal ground 12 in the bending region, which affects the isolation effect of the signal line 21 and further affects the signal transmission effect in the signal line 21. The power line 22 and the control line 23 do not need to have the same isolation effect as the signal line 21, and therefore the structure of the bent region does not have a large influence on the power line 22 and the control line 23.

In order to alleviate the influence of the bent structure of the bending region on the transmission quality of the signal line 21, in some embodiments of the present application, the buffer hole 4 is disposed in an orthographic projection region of the power line 22 and the control line 23 to the top layer metal ground 11 and the bottom layer metal ground 12.

For example, as shown in fig. 1 and 4, when the signal line 21 is disposed in the middle region of the signal layer, the buffer hole 4 may not be disposed in the middle regions of the top-layer metal ground 11 and the bottom-layer metal ground 12, and the buffer hole 4 may be disposed in the top-layer metal ground 11 and the bottom-layer metal ground 12. In the bending region, a circular window is formed in the region of the top layer metal ground 11 and the bottom layer metal ground 12 of the flexible transmission line. In order to ensure that the energy of the radio frequency signal is not lost, windowing and copper removing processing is not performed on the top layer metal ground 11 (a forward projection area towards the top layer metal ground 11) above the signal wire 21 and the bottom layer metal ground 12 (a forward projection area towards the bottom layer metal ground 12) below the signal wire, and windowing is performed only on the top layer metal ground 11 and the bottom layer metal ground 12 corresponding to the power wire 22 and the control wire 23, so that the overall hardness (or rigidity) in a bending area is reduced, and the transmission wire is convenient to bend.

In addition, for the transmission line, no metalized via hole is formed in the bending area, namely, no metal column 5 is arranged, so that the transmission line is prevented from being broken when a product is bent.

In the technical scheme provided by the application, dielectric layer 3 can be combined with metal ground 1, signal layer 2 and internal wiring to form the whole multilayer structure of transmission line, and can also carry out isolation protection to internal wiring, namely signal line 21, power cord 22 and control line 23. Obviously, the dielectric layer 3 in the bending region also has a bending structure along with the whole bending of the transmission line, so the dielectric layer 3 should also be made of soft material. That is, in some embodiments of the present application, the dielectric substrate of the dielectric layer 3 is LCP, MPI, or PTFE. The base materials have good bending property and low loss, and can reduce the loss of signals to a certain extent. In practical application, a suitable dielectric substrate can be selected according to different terminal equipment characteristics and working environments in which the transmission line is applied.

The LCP (Liquid Crystal Polymer) material is a special engineering plastic raw material, namely soluble poly-p-phenylene terephthalamide, has excellent heat resistance and forming and processing properties, and can be conveniently deformed into a bending structure to meet the bending requirement of a transmission line. The MPI (Modified PI) material is an amorphous material, has better flexibility and sealing property, and can also meet the bending requirement of a transmission line. PTFE (polytetrafluoroethylene) material is a sealing material and filling material, has easy shaping, corrosion-resistant characteristics, can have better stability under the prerequisite of the demand of bending of adaptation transmission line, improves the life of transmission line.

In some embodiments of the present application, the flexible transmission line further includes a connector 6. The connector 6 may be used to connect specific signaling devices. Obviously, in order to realize signal transmission between two devices, the connectors 6 are disposed at two ends of the flexible transmission line, and the connectors 6 at the two ends are respectively used for connecting different devices. For example, the connector 6 at one end is connected to the antenna, and the connector 6 at the other end is connected to the terminal main board, so that the signal transmission is completed between the terminal main board and the antenna. The structure of the connector 6 may have a different interface structure according to the interface specification corresponding to the connected device. Meanwhile, the connector 6 connects the signal layer 2, i.e. the connector 6 needs to be connected with the signal line 21, the power line 22 and the control line 23 to transmit signals.

According to the above technical solution, the present application provides an easily bendable flexible transmission line, which includes a metal ground 1, a signal layer 2, and a dielectric layer 3. The metal grounds 1 form a multi-layer structure of the transmission line, the dielectric layer 3 is filled between the metal grounds 1, and the signal layer 2 is embedded in the dielectric layer 3. The top metal ground 11 positioned on the top surface of the medium layer 3 and the bottom metal ground 12 positioned on the bottom surface of the medium layer 3 are provided with buffer holes 4 in the bending area. The transmission line that this application provided can make soft transmission line can accomplish required processing of buckling under the prerequisite of guaranteeing soft transmission line radio frequency performance through windowing in the region of buckling and subtract the copper design to it can also alleviate the technology degree of difficulty to subtract copper in the region of buckling. The problem of traditional soft transmission line resilience force and the degree of difficulty of bending are big, be not convenient for bend is solved.

It should be noted that the above embodiments describe the transmission line structure provided in the present application by taking the upper, middle and lower three-layer structures as examples. The metal ground 1 of the upper layer and the lower layer is positioned on the surface layer outside the soft transmission line dielectric layer, and the middle layer, namely the signal layer is positioned in the middle of the dielectric substrate and is embedded in the dielectric substrate. Therefore, the top layer metal ground 11 and the bottom layer metal ground 12 can play a role in shielding interference besides the function as a reference ground, and play a role in assisting electromagnetic compatibility processing inside the terminal equipment. Obviously, the structure of the transmission line is not limited to the three-layer structure, and can be flexibly designed according to actual requirements, and can be applied to four or more layers of flexible transmission lines.

The embodiments provided in the present application are only a few examples of the general concept of the present application, and do not limit the scope of the present application. Any other embodiments extended according to the scheme of the present application without inventive efforts will be within the scope of protection of the present application for a person skilled in the art.

Claims (9)

1. The flexible transmission line easy to bend is characterized by comprising a metal ground (1), a signal layer (2) and a dielectric layer (3); the dielectric layer (3) is filled among a plurality of layers of metal grounds (1), and the signal layer (2) is embedded in the dielectric layer (3);

the multilayer metal ground (1) comprises: a top metal ground (11) positioned on the top surface of the dielectric layer (3) and a bottom metal ground (12) positioned on the bottom surface of the dielectric layer (3); and the top layer metal ground (11) and the bottom layer metal ground (12) are provided with buffer holes (4) in the bending area so as to improve the bending performance of the flexible transmission line.

2. The flexible transmission line of claim 1, further comprising a metal post (5); the metal column (5) penetrates through the multiple layers of metal grounds (1) to connect the top layer metal ground (11) and the bottom layer metal ground (12) and isolate the signal layer (2).

3. The flexible transmission line of claim 2, wherein the signal layer (2) comprises a signal line (21); the metal posts (5) are arranged on two sides of the signal line (21) to improve the isolation of the signal line (21).

4. The flexible transmission line of claim 3, wherein the signal layer (2) further comprises a power line (22) and a control line (23); the power line (22) and the control line (23) are embedded in the dielectric layer (3); the power line (22) and the control line (23) are respectively arranged on two sides of the signal line (21) so as to isolate the signal line (21), the power line (22) and the control line (23) through the metal column (5).

5. The flexible transmission line of claim 4, wherein the buffer hole (4) is disposed in an orthographic projection area of the power line (22) and the control line (23) to the top metal ground (11) and the bottom metal ground (12).

6. The transmission line of claim 1, wherein the buffer holes (4) are a plurality of open-cell structures uniformly arranged in the bending region.

7. The transmission line of claim 1, wherein the buffer hole (4) is a hollow structure disposed in the bending region.

8. The flexible transmission line of claim 1, wherein the dielectric substrate of the dielectric layer (3) is LCP, MPI, or PTFE.

9. The flexible transmission line of claim 1, further comprising a connector (6); the connectors (6) are arranged at two ends of the flexible transmission line; the connector (6) is connected with the signal layer (2) to transmit signals.

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